New Year's Resolution for 2017: Make a D3 Block a day to teach myself D3. This is Number 6. This example is my first map example and shamelessly copies a neat example by Michelle Chandra. This example tweaks some of the tooltip stylings but keeps everything else pretty much the same.
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<meta charset="utf-8">
<head>
<title>D3 Block-a-Day: Day 6, January 6, 2017</title>
<script src="https://d3js.org/d3.v4.min.js"></script>
<style type="text/css">
/* On mouse hover, lighten state color */
path:hover {
fill-opacity: .8;
}
/* Style for Custom Tooltip */
div.tooltip {
position: absolute;
text-align: center;
width: 80px;
padding: 7px;
font: 12px Helvetica Neue;
background: #fff8dc;
border: 2px solid;
border-color: black;
border-radius: 3px;
pointer-events: none;
box-shadow: rgba(0, 0, 0, 0.3) 0 2px 10px;
}
/* Legend Font Style */
body {
font: 11px Helvetica Neue;
}
/* Legend Position Style */
.legend {
position:absolute;
left:800px;
top:350px;
}
</style>
</head>
<body>
<script type="text/javascript">
/* This visualization was made possible by modifying code provided by:
Michelle Chandra’s Block 0b2ce4923dc9b5809922
https://gist.github.com/michellechandra/0b2ce4923dc9b5809922 */
//Width and height of map
var width = 960;
var height = 500;
// D3 Projection
var projection = d3.geoAlbersUsa()
.translate([width/2, height/2]) // translate to center of screen
.scale([1000]); // scale things down so see entire US
// Define path generator
var path = d3.geoPath() // path generator that will convert GeoJSON to SVG paths
.projection(projection); // tell path generator to use albersUsa projection
// Define linear scale for output
var color = d3.scaleLinear()
.range(["rgb(213,222,217)","rgb(69,173,168)","rgb(84,36,55)","rgb(217,91,67)"]);
var legendText = ["Cities Lived", "States Lived", "States Visited", "Nada"];
//Create SVG element and append map to the SVG
var svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);
// Append Div for tooltip to SVG
var div = d3.select("body")
.append("div")
.attr("class", "tooltip")
.style("opacity", 0);
// Load in my states data!
d3.csv("states-lived.csv", function(data) {
color.domain([0,1,2,3]); // setting the range of the input data
// Load GeoJSON data and merge with states data
d3.json("us-states.json", function(json) {
// Loop through each state data value in the .csv file
for (var i = 0; i < data.length; i++) {
// Grab State Name
var dataState = data[i].state;
// Grab data value
var dataValue = data[i].visited;
// Find the corresponding state inside the GeoJSON
for (var j = 0; j < json.features.length; j++) {
var jsonState = json.features[j].properties.name;
if (dataState == jsonState) {
// Copy the data value into the JSON
json.features[j].properties.visited = dataValue;
// Stop looking through the JSON
break;
}
}
}
// Bind the data to the SVG and create one path per GeoJSON feature
svg.selectAll("path")
.data(json.features)
.enter()
.append("path")
.attr("d", path)
.style("stroke", "#fff")
.style("stroke-width", "1")
.style("fill", function(d) {
// Get data value
var value = d.properties.visited;
if (value) {
//If value exists…
return color(value);
} else {
//If value is undefined…
return "rgb(213,222,217)";
}
});
// Map the cities I have lived in!
d3.csv("cities-lived.csv", function(data) {
svg.selectAll("circle")
.data(data)
.enter()
.append("circle")
.attr("cx", function(d) {
return projection([d.lon, d.lat])[0];
})
.attr("cy", function(d) {
return projection([d.lon, d.lat])[1];
})
.attr("r", function(d) {
return Math.sqrt(d.years) * 3;
})
.style("fill", "rgb(217,91,67)")
.style("opacity", 0.85)
.style("stroke", "#fff")
.style("stroke-width", "1")
// Modification of custom tooltip code provided by Malcolm Maclean, "D3 Tips and Tricks"
// https://www.d3noob.org/2013/01/adding-tooltips-to-d3js-graph.html
.on("mouseover", function(d) {
div.transition()
.duration(200)
.style("opacity", .9);
div.text(d.place)
.style("left", (d3.event.pageX + 10) + "px")
.style("top", (d3.event.pageY - 30) + "px");
})
// fade out tooltip on mouse out
.on("mouseout", function(d) {
div.transition()
.duration(500)
.style("opacity", 0);
});
});
// Modified Legend Code from Mike Bostock: https://bl.ocks.org/mbostock/3888852
var legend = d3.select("body").append("svg")
.attr("class", "legend")
.attr("width", 140)
.attr("height", 200)
.selectAll("g")
.data(color.domain().slice().reverse())
.enter()
.append("g")
.attr("transform", function(d, i) { return "translate(0," + i * 20 + ")"; });
legend.append("rect")
.attr("width", 18)
.attr("height", 18)
.style("fill", color);
legend.append("text")
.data(legendText)
.attr("x", 24)
.attr("y", 9)
.attr("dy", ".35em")
.text(function(d) { return d; });
});
});
</script>
</body>
</html>
Modified http://d3js.org/d3.v4.min.js to a secure url
https://d3js.org/d3.v4.min.js